The objectives of this study are to examine changes in genetic control of subspecies of cytochrome P-450 in the rat after treatment with polychlorinated biphenyls (PCBs), 2,3,7,8-tetrachloro-p-dibenzodioxin (TCDD) and other environmental chemicals and to assess the implications of these changes. Present work includes immunoprecipitation and in vitro translation of messenger RNAs for various P-450's after treatment with PCBs and other environmental chemicals. Changes in translation and isozyme content will be examined with time and dose of inducer. Antibodies are being raised to additional forms of rat liver P450 to be used as probes for quantitating changes due to environmental chemicals and other factors such as hormones and aging. We will attempt to clone DNA complementary to some of the rat P450s to use to analyze gene structure and changes in protein and mRNA synthesis after exposure to various chemicals. The goal of this project is to better understand the changes occurring at the genetic level after exposure to environmental chemicals.